A non-contact power supply system is a system for receiving AC current from a power supply side in a non-contact manner at a power reception side by electromagnetic induction, and application has been studied for a system that supplies power in a non-contact manner from a ground side to a drive motor during parking.
In particular, in the non-contact power supply system applied for a power supply method to a mobile body, there is a problem that foreign matter mixed into the non-contact power supply system becomes a heating element. Specifically, when foreign matter is mixed between a power supply coil and a power reception coil, foreign matter such as a metal or a magnetic substance may be heated due to magnetic flux passing through the foreign matter.
Patent Literature 1 discloses a foreign matter detection device for sensing foreign matter existing near a sensing coil without newly providing a sensor. Specifically, presence of foreign matter is determined by detecting an electrical change in the sensing coil that due to the foreign matter.